This invention relates in general to gas turbine engine thrust reversers and, more specifically, to an improved torque ring assembly for transferring aerodynamic loads from a thrust reverser back to the engine casing.
Gas turbine engines of several types have come into widespread use with large passenger aircraft. In order to reduce aircraft ground speed after landing, most such engines include a thrust reverser of some sort to direct engine thrust from the normal aft direction to a more forward direction, thus using engine thrust to dynamically reduce aircraft speed.
A large variety of thrust reversers have been designed for use with different gas turbine engines. Some use simple, large and sturdy "clamshell" mechanisms in which large deflector doors are pivoted from position out of the engine outlet thrust path to a position substantially blocking the outlet flow and directing it in a forwardly direction. Typical of these are the thrust reversers described by Feld et al in U.S. Pat. No. 3,550,855 and by Johnson in U.S. Pat. No. 2,871,656.
The deflector door or clamshell system is not suitable for use with fan type gas turbine engines. Fan jets include a core engine surrounded by a tubular nacelle defining a bypass duct between nacelle and core. A fan at the engine inlet, driven by the core engine, directs a compressed air flow through the bypass duct. A number of different thrust reversers have been developed for fan jet engines. In general, they include a ring of openings through the nacelle which contains a turning vane cascade. An actuator moves a cover between positions uncovering and covering the openings. Blocking doors aft of the cascade are movable between a first position in which bypass duct air flow is unhindered and a second position in which air flow through the bypass duct is blocked and forced through direction, serving to reverse thrust direction and slow the aircraft. Typical of these fan jet cascade type thrust reversers are those described by Hom et al in U.S. Pat. No. 3,500,646 and Maison in U.S. Pat. No. 3,601,992.
The turning vane cascade and cover actuator mounts are subjected to severe aerodynamic loading during high speed thrust reversal. They must be mounted to the relatively thin nacelle adjacent to the engine casing in a manner which does not obstruct bypass duct flow during normal engine operation. Complex mounting arrangements tend to be less reliable, add undesirable weight and be difficult to service.
Many of the present cascade type thrust reversers operate satisfactorily. However, there is a continuing need for improved arrangements for mounting and supporting the cascade and actuator to improve simplicity and reliability and reduce weight while providing optimum air flow to the cascade during thrust reversal.